Half-duplex morse carrier system



Oct. 28 1924.

1.. E SPENSCHIED HALF DUPLEX MORSE CARRIER SYSTEM Filed Aug. 11. 1921 2 Shama -Sheet 2 Patented 0a. 28, 1924;

UNITED STATES PATENT OFFICE.

LLOYD Esr NscmEn, or QUEENS, NEW YoEK, AssmNon TO AMERICAN TELEPHONE AND'TELEGRAPH comrniw, a conrom-rron or NEW, Yonx.

HALF-DUZPLEX MbRSE CARRIER SYSTEM.

Application filed August 11, 1921. Serial No. 491,509.

Toall whom it may concern:

Be it known that I, LLOYD ESPENSCHIED, residing at Queens, in the county of Queens and State of New York, have invented cer-' tain Improvements in Half-Duplex Morse Carrier Systems, of which the following is a specification. I

This invention relates to signaling systems, and more particularly to multiplex signaling systems employing carrier currents for transmission purposes.

One of the purposes of this invention is to produce a simple terminal apparatus for half-duplex Morse operation over carrier channels. A salient feature of the terminal arrangement is that. the same vacuum tube is employed both as a receivingdetector and as an oscillation tube-for sending signals. Switching arrangements are provided for determining whether the tube shall function in the one capacity or the other, and these switching arrangements are under the control of an ordinary Morse repeater set, so that the functioning-of the tube may be controlled from the subscribers loop and signals may be repeated to the subscribers loo ther and further features .of the invention will be clear from the following description, when read in connection with the accompanying drawing, Figure 1 of wh ch illustrates the invention as applied to a single tube which functions both as a detector and as an oscillator, while Fig. 2 illustrates the invention as applied to two tubes, one of which functions as an amplifier and the other as a detector when receiving, while both tubes function to generate oscillations when transmitting.

' Referring to Fig. 1., ML designates a main transmission line terminating in selective circuits F F F etc., the selective circuit arrangements being adapted to associate the main line with terminal carrier channels. The carrier apparatus associated with but one of the selective devices is illustrated, but it will be understood that similar apparatus will be provided for each channel. The apparatus associated with the selective device I includes a vacuum tube VT of the usual three-element type. A tuned circuit or other selective device F, is included in the grid circuit of the vacuum tube. This tuned circuit is coupled with the tuned circuit or selective device F and renders the vacuum tube selective of the received carrier fre quency when receiving, and serves to deter-' mine the frequency of the" vacuum tubelay RRQ The polar relay RR operates upon the attenuating current component of the received signal and its armature is unbiased so that it will rest upon either'contact when no signal impulses are received.

The tuned circuits F and F are coupled together through windings 10 and 11 ofa transformer, and a third winding 12, ar-- ranged in inductive relation tothe windings 1 and 11, is connected in the plate filament circuit. The-plate circuit may, if'desired. mclude a blocking condenser 14 to prevent the direct current from the plate battery from flowing through the relay RR or into the feed-back connection. relay TR is provided, this relay being controlled by the transmitting relay TR of the loop repeater, as will be described later. The transmitting relay TR is normally energized and inthis condition establishes a connection from the filament through windings 12 and 11 in series to the grid of the vacuum tube VT. -The grid circuit includes the usual grid battery 15, which applies such a potential to the grid circuit as to enable it to function as a detector. When the transmitting relay TR is deenergized in response to signals from the loop, it establishes a connection from the filament to the junction point between the windings '11 and 12 through an auxiliary battery 16. The winding 11 is now included in the grid circuit and the winding 12 in the plate circuit, so that a feed-back connection is established. Battery 16 is also connected in series with the battery 15, so that" the potential now applied to the grid isv such that the tube functions most efficiently as an oscillator. The extra contact upon the relay TR short cir: cuits the receiving relay R "to prevent it from chattering in response to the oscillations generated.

The loop L includes a transmitting key K, a sounder controlling relay S, and the winding of the magnet 21 of the loop transmitting relay TR. The relays TR and RR are each provided with auxiliary magnets A transmitting circuit of the transmitting relay TR through its armature.

' Under normal conditions .when the key K is not operated to transmit signals, the circuit of the loop L is closed and the winding 21 of the relay TR is energized. .The winding 20 of the loop controlling relay RR is also energized when signals are not being received, and under these conditions the winding of magnet 21 is short-circuited by the contact of relay RR and the winding of -magnet 20 is short-circuited by the contact of relay TR. .Relay TR holds the transmitting relay TR energized and the windings 11 and 12 of the vacuum tube circuit are serially included in the grid circuit, so that the vacuum tube is in condition to function as a detector. The short circuit about the winding of relay- RR is also held open by relay TR. If signals are received with the circuits in this condition, the polar receiving relay RR is operated in response to the alternating component of the detected signals to open-the circuit of the winding 20 of the loop controlling relay RR. As the winding 20' of this relay is short-circuited, the armature of the relay falls off and opens the loop circuit to operate the loop sounder. As the armature of the relay RR falls "off, it opens the circuit of the magnet 21 of the loop transmitting relay TR, but at the same time the short-circuit about the winding of the holding magnet 21 of the relay TR is removed, so that the holding magnet prevents the armature of the relay TR from being retracted to repeat the received signal back to the main line ML.

ing of the holding magnet 21 of the loop controlling relay RR is removed at the same time, so that the relay RR is locked up to prevent the opening of the loop independently of the key K, in case the receiving relay RR should happen to respond to the transmitted signals. The receiving relay RR is however prevented from operating by the shunt circuit closed by relay TR The transmitting relay TR when deenergized connects the filament to the junction point of the windings 11 and 12, so that the circuit of the tacuum tube VT is changed from a detecting circuit to ,an oscillating circuit. The tube then generates oscillations at a frequency determined by its tuned circuit F, and these oscillations are transmitted to the main line ML so long as the key K is held open. In this manner groups of oscillations representing dots and dashes may be transmitted to the main line.

A modified form is illustrated in Fig. 2, in which two tubes are provided, one normally functioning as an amplifier and the other as a detector, and the circuits being so arranged that when signals are to be transmitted, the two tubes will function in tandem as a generator of oscillations. In the diagram of Fig. 2, VT designates the tube which normally functions as an amplifier and VT, designates a tube which normally functions as a detector. The plate circuit of the tube VT, has associated therewith a polar receiving relay RR similar to that described in connection with Fig. 1 for actuating the loop controlling relay RR of the mechanical repeating arrangement in the same manner as in Fig. 1. Two transmitting relays TR and TR, are provided, these transmitting relays being controlled by the relay TR in the loop circuit to transmit signals. Normally the relays TR and TR, are energized, the former maintaining a connection from. the filaments of the two tubes through the condenser 14 and the windings 12 and 11 in series to the grid of the tube VT,. A connection is at the same time maintained from the filaments of the two tubes through the winding of the polar relay RR. to the plate of the tube VT,. The relay TR maintains a connection from the grid of the tube VT, to the filament through a polarizing battery of such potential and polarity as to apply a potential to the grid of the tube VT, which will render it most efiicient as a detector. With the circuit arrangement in this condition, high frequency oscillations will be amplified by the'tube VT and detected' by the tube VT, whereby the attenuating component of the detected signal actuates the polar receiving relay RR which will repeat the signals through the relay RR of the repeater to the loop L in a man ner similar to that described. in connection with Fig. 1.

Relays TR and TR, are so arranged that whent ey are deenergized the former breaks the connection from the filaments of the two tubes to the grid otthetube VT and to the plate of the tube VT, reviously described, and connects the two laments to the junction point of the windings 11 and 12. A feed-back connection is now established from Y denser shunting the receiving rela the plate of the tube VT through the (i211;-

. through the condenser 14 and the win ing 12 and over the contact of the relay TR, to the filaments of the tubes VT and VT,,. The energy from the plate circuit of the tube VT will, therefore, be transmitted back through the windin 12 and through the inductive connection etween the windings 11 and 12 will be impressed upon the grid circuit of the tube VT,. This energy will be amplified by the tube VT and then im-' pressed upon the grid circuit of the tube VT, to be again amplified and impressed upon the feed-back circuit, so that the com' bination of tubes functions as a generator of oscillations. The relay TR when deenergized short circuits relay RR and shifts the connection between the filament and grid of the tube VT so as to change the polarizing battery connection in such a manner as to apply a potential to said tube of such polarity and value as to render the tube most efficient as an am lifier or oscillator,

thereby assisting in ren ering the system an eflicient generator of oscillations. Signals may be transmitted by opening the loop circuit in the manner described in connection with Fig. 1, thereby causing the relays TR and TR to be deenergized'for each dot and many other organizations widely different from those illustrated, without departing from the spirit of the invention as defined in the following claims. i=

What is claimed is: 1. Ina signaling system, a

therewith, said carrier apparatus including a translating device which under certain conditions functions as a detector and under other conditions functions as a generator of oscillations, a subscribers loop and mechanical repeating apparatus associated therewith, said mechanical' repeating apparatus operating when said translating device functions as a detector to repeat the detected signals to the loop, and operating when sig nals originate in the loop to cause said trans lating device to function as a generator of oscillations.

circuit and carrier apparatus associated therewith, said carrier apparatus including a vacuum tube which under certain conditions functions as' a detector and under other 'conditionsfunctions as a generator of oscilgenerat-' lations.

ing when said vacuum tube functions as a detector to repeat the detected signals to the. loop and operating when signals originate in the loop to cause said vacuum tube to function as a generator of oscillations.

3. In a signaling system, a transmission circuit and carrier apparatus associated therewith, said carrier apparatus including a translating device which under certain con d1t1ons functions as a detector and under other conditions functions as a generator of for repeating to the loop signals detected by said' translating ,device when functioning as a detector, said first relay operating in response to signals originating in the loop .to cause said translating device to generate oscillations.

4.- In a signaling system,'a transmission circuit and carrier apparatus associated therewith, said carrier apparatus including a vacuum tube which under certain conditions functions a'sa detector and under other conditions functions as agenerator of oscillations, a subscribers'loo'p and mechanical repeating apparatus associated with said subscribers loop and including a relay arrangement-for re eatin signals originating in the loop an 'anot errelay arrangement for repeating. to the loop signalsdetected b said vacuum tube when function: ing as a etector, said first relay operating in response to signals originating in the loop to cause said vacuum tube to generate oscil- 5. In a signaling. system, a transmission a circuit and carrier apparatus associated transmission circuit and carrier apparatus associatedtherewith, said carrier apparatus including a translating device which under certain conditionsfunctions as a detector and under other conditions functions as a generator of oscillations, a ,subsc-ribers loop, mechanical repeating apparatus associated with said subscribers loop and including a relay arrangement' for repeating signals originating in the loop' and another relay arrangement for repeatingto the loop signals detected by said translating device when functioning as.

a detector, said first-relay operating in response to signals originating in the loop to cause said translating device togenerate os- H cillations, and means associated with said re- 2. In a signaling system, a transmiss on? 4 6.- Ina signaling system, a transmission circuit and'fcarrier apparatus associated therewith, said carrier apparatus including a vacuum tube which under certain conditions functions as a detector and under other coning means for establishing a feed-back con ditions functions as a generator of oscillations, a subscribersiloop, mechanical repeating apparatus associated with said subscri'ber s loop and including a relay arrangement for repeating signalsoriginating in the loop and another relay arrangement for repeating to the loop signals detected by said vacuum tube when functioning as a detector, said first relay operating in response to signals originating in the loop to cause said vacuum tube to generate oscillations, and means associated with said relays. to prevent'reeeived signals from operating said first mentioned relay and to prevent transmitted signals from operating said second relay.

7. In a signaling system, a transmission circuit and carrier apparatus associated therewith said carrier apparatus including a vacuum tube, means associated with said tube for producing a normal, steady difi'erence of potential between the grid and filament of said tube independentof signaling currents applied thereto whereby the tube normally functionsas a detector, and switching meansto change the normal difierence in potential between the grid and filament of the tube so that the tube may function eficiently as an oscillator.

8. In a signaling system, a transmission circuit and carrier apparatus associated therewith said carrier apparatusirrcluding a vacuum tube, means associated with said tube for producing .a normal, steady difference in potential between the grid and plate of the tube independent of any signaling currents applied thereto whereby the tube normally functions as a detector, and switchnection between the grid and plate of said tube and for changing the normal, steady:

potential difierence between the grid and filament of the tube so that the tube will function as a generator of oscillations.

9. In a signaling system, a transmission circuit and carrier apparatus associated therewith, said carrier apparatus including a vacuum tube which normally functions as a detector, and switching means for normally establishing a connection from the filament of said vacuum tube through two windings of a transformer to the grid, said nsraaeo switching means being so organized that under certain conditions the filament will be connected to the junction point of the two windings so as to establish an oscillating feed-back connection between the grid and plate.

10. In a signaling system, a transmission circuit and carrier apparatus associated therewith, said carrier apparatus including "a vacuum tube which normally functions as -a detector, and switching means for normally establishing a connection from the a vacuum tube normally functioning as an amplifier and another vacuum tube normally functioning as a detector, and a switching device normally establishing a connection'between the filaments of said tube and through two windings in series to the grid of the first tube, a connection being simultaneously established from the filamentsof the tubes to the plate of the second tube, said switching apparatus being so organized that under certain conditions a connection may beestablished from the filaments to the junction point of the two windings, so that a feedback connection is' established between the plate of the second tube to the grid of the first tube, said switching arrangement also simultaneously operating to change the potential applied to the gridof the second tube to render said tube most eficient as an oscillator. I a

In testimony whereof, I have signed my nameto this specification this 9th day of August, 1921.

LI1OYI) ESPENSCIIIED. 

